Checking file system on C:
The type of the file system is NTFS.
Cannot open volume for direct access.
Windows has finished checking the disk.
....

It then fails to boot - the whole process stops there.

Last time I remember booting the computer, it worked fine. There was the same message about checking the disk, and "cannot open volume", but it still booted fine. I don't remember making any changes, I just turned it off, expecting it to boot up again next time, but it doesn't.

There is only one hard drive in the machine, and it does not have network access (no ethernet cable plugged in), so it's not going to be halting because of any updates or anything.